This invention generally relates to a thermal conditioning system for wind turbines and, more particularly, to a thermal conditioning system for off-shore wind turbines.
Wind turbines are devices that convert mechanical energy to electrical energy. A typical wind turbine includes a nacelle mounted on a tower housing a drive train for transmitting the rotation of a wind rotor to an electric generator through, usually, a gearbox, and other components such as a yaw drive which rotates the wind turbine, several controllers and a brake. The wind rotor comprises a rotor hub supporting a number of blades extending radially therefrom for capturing the kinetic energy of the wind and causing the driving train rotational motion.
Some components of the wind turbine, particularly the gearbox and the generator are coupled to heat exchangers.
Known thermal conditioning systems of on-shore wind turbines combine the use of ambient air to cool the nacelle with the installation of heat exchangers associated to particular wind turbine components.
In case of off-shore wind turbines, there is a need for the treatment of air supplied for the thermal conditioning of the nacelle, due to the moisture content and the salinity of sea air. These properties of sea air could affect the working conditions and life of the nacelle components and so air treatment is required. Due to the bulkiness of the air-treatment plant, it can be placed at the base-level of the wind turbine and the treated air can be pumped to the nacelle through a duct inside the tower.
Taking into account the high powers foreseen for off-shore wind turbines, the use of high power, big size, and heavy weight air-treatment plants seems necessary. The cost of these plants may be very high.
During the air transport from the base-level to the nacelle, there are thermal losses to its surroundings due to convection because of the different temperature of the treated air with respect to the temperature of the air inside the tower.
A conventional insulation of the duct would indeed reduce the thermal losses along the duct but the insulation costs may not compensate the energy savings.